THE FLOWERLE88 PLANTS. 



37 



turity they swim, 

 when the prothal- 

 lium is wet with 

 rain or dew, to the 

 o o sp h e r e s, enter 

 and unite with 

 them. An do spore 

 is the result of this 

 union, and this 

 oospore grows into 

 an ordinary Fern 

 plant. If prothal- 

 lia are not pro- 

 duced by the cul- 

 ture on moist sand, 

 they may often be 

 found on the soil or 

 pots in which Ferns 

 are cultivated. A 

 neglected fernery 

 is quite sure to 

 yield specimens. 



After a Fern 

 plant has once 

 started by this 

 mode of reproduc- 

 tion, it lives many 



years. The Stem FIG. 15. Prothallium of a Fern, exhibiting the 

 I r 1-1 reproductive organs. At the sinus of the heart- 



uaiiy wnoiiy shape d film are to be seen the archegonia, one 



of which, more highly magnified, is displayed in 

 section in A. B, an enlarged antheridium, with 

 escaping antherozoids. (Luerssen.) 



underground, only 

 the leaf rising 

 above ground. 



5. Try to identify the common Ferns of your neigh- 

 borhood by analyzing with the help of Gray's " Manual " 

 or Underwood's " Our Native Ferns and their Allies." 



